Energy-efficient washing machine in a German hospital acted as a pathogen reservoir

Energy-efficient washing machines could be harbouring dangerous antibiotic-resistant bacteria as they do not run hot enough to destroy them, a new study found.

Researchers found that a washing machine used on the clothes of babies in intensive care in Germany was harbouring pneumonia-like bacteria in trapped water.

It is also thought that the final rinse — which uses unheated water — could also have helped cultivate the bacterial contamination.

The rise in popularity of energy-saving, low-temperature washes — which are less capable of destroying microorganisms — could be dangerous, they warned.

To address this, the team are calling for eco-friendly machines to be redesigned to make them safer at their lower temperatures.

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Energy-efficient washing machines could be harbouring dangerous antibiotic-resistant bacteria as they do not run hot enough to destroy them, a new study found

‘Water temperatures used in home washers have been declining, to save energy, to well below 60°C (140°F),’ said lead researcher Dr Schmithausen, of Germany’s Boon University.

This, she explains, is ‘rendering them less lethal to pathogens.’

‘Resistance genes, as well as different microorganisms, can persist in domestic washing machines at those reduced temperatures.’

Elderly people who do their laundry at home are at particular risk from this issue, as their clothes can often be contaminated by infectious bacteria from wounds and other ailments.

‘This is a growing challenge for hygienists, as the number of people receiving nursing care from family members is constantly increasing,’ said Martin Exner, also of the University of Bonn.

‘Laundry should be washed at higher temperatures, or with efficient disinfectants, to avoid transmission of dangerous pathogens if elderly people require nursing care with open wounds or bladder catheters.’

However, younger people with infections are similarly at risk if they do their laundry at home in a low-temperature, energy saving wash.

Researchers found that a washing machine used on the clothes of babies in intensive care in Germany was harbouring pneumonia-like bacteria in trapped water

Researchers reported the risks of energy-saving domestic washers after finding a one such machine, used in a German hospital, that contained microscopic pathogens called Klebsiella oxytoca.

The machine had been used in a neonatal intensive care unit to wash babies’ clothes that keep them warm in incubators — like socks and knitted caps — but was accidentally contaminating them in the process.

The babies were in the intensive care unit following either premature birth or an unrelated infection. 

Having detected the pathogen’s colonisation of the babies’ clothing during a standard screening, the researchers ruled out both the incubators and health care workers as the source of the bacteria before identifying the contaminated machine.

It is not known how the detected pathogens — which were lurking in water trapped within the machine’s rubber mantle — had got into the washer in the first instance.

‘This is a highly unusual case for a hospital, in that it involved a household type washing machine,’ said Dr Schmithausen.

‘Hospitals normally use special washing machines and laundry processes that wash at high temperatures and with disinfectants, or they use designated external laundries.’

In addition, the researchers noted that the final rinsing process, which uses unheated and detergent-free water, could also be spreading hostile bacteria.

‘The study implies that changes in washing machine design and processing are required to prevent the accumulation of residual water where microbial growth can occur and contaminate clothes,’ said Dr Schmithausen.

Although the pathogens are capable of resisting several antibiotics, they did not harm the babies in this instance.

The full findings of the study were published in the journal Applied and Environmental Microbiology.